The new Panasonic Lumix GH6 is one of the most powerful video cameras on the market, but it lacks phase-detect focusing, which is a minor flaw. Panasonic has finally clarified why the new camera is still using outdated AF technology.
Panasonic USA’s Business Development Manager Matt Frazer said during the GH6 launch that he was “well aware it isn’t the direction that people were hoping for us to go” with the camera’s autofocus, but that “it just wasn’t possible for us to get a modification for phase-based autofocus” on the new sensor.
The GH6 features a kind of contrast-detect focusing termed ‘Depth by Defocus,’ just as prior Panasonic cameras (DFD). Contrast-detect autofocus works by adjusting the focusing distance of the lens to determine where the highest contrast exists. It’s great for still images, and DFD adds topic detection to assist enhance speed and accuracy.
Most other camera manufacturers, on the other hand, employ ‘hybrid’ AF systems that combine contrast-based and phase-detect focusing (PDAF) to remarkable effect. Phase-detection works by dividing the incoming light into two pictures and then adjusting the focus to align the two views. It’s usually quicker than contrast-based AF and better at tracking moving subjects, but it might have unintended consequences for other elements of a sensor’s design, which is one of the reasons Panasonic didn’t use it on the GH6.
“You have to remember that when we’re developing or working on a sensor design, we’re working on the information based on an older camera – we were working on this around the GH4’s timeline,” Frazer explained, referring to the camera that came out in 2014. “You’re working on the concerns of the sensor at that point. So low-light sensitivity, dynamic range, resolution – those are things people were most concerned about.”
However, those weren’t the only things people wanted. “Obviously, we pay notice,” he continued, “since we know people are seeking for a PDAF solution.” However, it appears that this could not be combined with the additional upgrades Panasonic wished to bring to the GH6.
“At the end of the day, when we were working on this sensor design, it just wasn’t possible for us to get a modification for phase-based autofocus,” Frazer said, stating that the priorities were instead faster read-out speeds and improved dynamic range.
Taking the wider view
Autofocus is an important feature of any camera, but its value varies depending on the type of photography you’re doing. If you usually photograph static scenes or prefer to manually pull video focus, as many Panasonic GH6 customers do, the DFD contrast-detect autofocus will likely be enough.
The lack of phase-detect focusing becomes a possible concern only when capturing moving subjects or filming videos alone, as many bloggers do. Despite advancements to Panasonic’s DFD technology, these remarks from Panasonic’s Frazer, together with the admission that “it’s not what users wanted,” imply that the company recognizes that the GH6’s autofocus has certain limits.
The biggest disadvantage of Panasonic’s contrast-based AF systems has always been a ‘pulsing’ in the background of films as it hunts for the point of highest contrast, so we’ll be interested to see if this is still the case with the GH6. Another possible drawback is that the face and eye detection on the GH6 is less successful in higher frame-rate settings, such as 4K/120p.
Still, the GH6’s focusing mechanism could be sufficient for your style of recording, and it’s crucial to note that autofocus is only one component that affects a camera’s video performance. While cameras like the Canon EOS R5 have superior hybrid AF systems, they are also prone to overheat, which shouldn’t be an issue with the GH6 thanks to its fan-cooled design.
The GH6 is also said to offer one of the greatest in-body stabilization systems available, making it a great tool for vloggers and YouTubers. We’ll have our complete judgment shortly, but in the meanwhile, read our hands-on Panasonic GH6 review for all of our initial impressions.